SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c25e576d1710178e6846bb35009947a53f7c26958efea6e93ab67058e48f39f3' 
  AND token = 'flfRVM19JP1oY3wAHGUHLYmRKlyV0Qcz8pKx9vFFqdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}